Exemplary embodiments of the invention relate to a method for the operation of a light unit for a vehicle and to a light unit.
In general, light units for vehicles are known from prior art, in particular vehicle headlights having a light source module, in which the light sources of the light source module can be controlled individually by means of a control unit coupled to the light source module. Vehicle headlights formed in such a way are also known as pixel headlights or matrix headlights.
German patent document DE 102 23 751 B4 discloses a method for combining graphic formats in a digital video pipeline. In the method, a pipeline connection matrix is selectively configured in order to establish an image path by means of one or more steps of a graphic pipeline and one or more steps of a bit table image pipeline and in order to deliver selected output data from one or more of the steps of one of the pipelines to selected inputs of one or more of the steps of the other of the pipelines. Here, an output step can be connected to an output from each of the pipelines (e.g., from a selected step both of the graphic and the bit table image pipeline). The connection between the pipelines can comprise a switching matrix that can be configured to lead outputs from one or more of the first plurality of (graphic) steps to a certain or selected next one of the first plurality of (graphic) steps and to a selected one of the second plurality of (bit table image) steps. German patent document DE 10 2011 108 384 A1 discloses a headlight for a vehicle having a plurality of lighting means in which the lighting means are arranged in a matrix having a first extension direction and a second extension direction perpendicular thereto. Here, the lighting means are controlled individually.
German patent document DE 10 2008 062 640 A1 discloses a vehicle headlight having a plurality of LED light sources that are combined in a common light source matrix emitting light. The individual LED light sources can be designed to be able to be switched on and/or switched off and/or dimmed in order to change a light distribution of the light source matrix emitting light. At least one light distribution is stored in a storage unit as a brightness value for each individual LED light source. An evaluating and control unit selects a stored light distribution depending on at least one received parameter and correspondingly controls the LED light sources of the light source matrix.
Exemplary embodiments of the invention is directed to an improved method for the operation of a light unit in comparison to the prior art, as well as an improved light unit, in which flicker effects are avoided or at least reduced.
In a method for the operation of a vehicle light unit, according to an embodiment, wherein the light unit comprises at least one light source module having several light sources and a control unit coupled to the light source module, and the light sources each comprise a predetermined number of brightness levels, a predetermined number of light sources is activated for setting a light distribution by the control unit, and a brightness level of each light source is set individually.
According to the embodiments of the invention, a predetermined number of light sources is combined by the control unit to form at least one controllable light source unit. In order to set a light distribution, the light sources that form the at least one light source unit are activated together, whereas the brightness level of each of the light sources of the activated light source unit is set individually.
The combination of several light sources to form a controllable light source unit allows a higher resolution of the brightness level in the light distribution because a number of brightness levels in the light source unit in comparison to a number of brightness levels of an individual light source is increased by the factor that comprises the number of light sources that form a light source unit. In other words, if “x” light sources are combined to form a light source unit, the number of brightness levels of the light source unit increases by “x” in comparison to the number of brightness levels of an individual light source. Thus, above all, flicker effects in a lower brightness region can be avoided or at least reduced.
Embodiments of the method are particularly advantageous, in particular, in vehicle headlights having a high number of light sources, for example so-called pixel headlights having light diode arrays because above a certain number of light sources the human eye can no longer individually distinguish these and thus a reduced local resolution caused by the combination of several light sources cannot be optically perceived.
According to embodiments, the at least one light source unit is formed from a number of light sources arranged adjacently to one another, such that a common beam point, which is optically perceived as a light source, is formed from several light sources for generating a light distribution. Preferably, here, several light source units are formed, such that the increased brightness resolution occurs as homogeneously as possible in the light distribution.
The light sources forming the at least one light source unit can here be arranged horizontally, vertically, or diagonally adjacent to one another. For example, rectangular or square adjacent regions of light sources can be combined to form a light source unit.
The control of which of the light sources are to combine to form a light source unit takes place using the control unit that transmits a corresponding piece of information from the control unit to the light source module and this then activates the combined light sources together. The piece of information can, for example, be transmitted by a control signal for generating a light distribution.
To individually set the brightness level of a controlled light source, the brightness level to be set is also transmitted from the control unit to the light source module.
Setting the light distribution and the brightness preferably takes place automatically, depending on a current driving situation of the vehicle, which can be determined, for example, from the state variables of the vehicle. The state variables are vehicle data, such as a steering angle, a speed, a yaw angle, longitudinal and transverse acceleration, as well as switch positions, and surrounding data, brightness values detected by means of a camera and/or other sensors, moveable and immoveable objects etc., for example.
The control unit and the light source module are coupled together via a data bus, e.g., a CAN-bus, to control the light source module by means of the control unit.
The light unit according to the invention comprises at least one light source module and one control unit coupled to the light source module, wherein the light source module comprises several light sources that each have a predetermined number of brightness levels, and wherein the control unit for setting a light distribution is formed in such a way that it combines a predetermined number of light sources to form at least one controllable light source unit and activates the light sources forming the at least one light source unit together and individually sets a brightness level of each of the light sources of the at least one activated light source unit.
The advantages obtained by embodiments of the invention include better resolution of the brightness as a result of reducing the local resolution by means of combining and setting the individual brightness of several light sources, which are combined to form a light source module.
Parts that correspond to one another are provided with the same reference numerals in all figures.